Tuning and turning of the liquid crystal alignment by photosensitive composites

To improve the characteristics and quality of the photoalignment of liquid crystals has been a main goal of many relevant studies. We demonstrate in this work, following the general concept of composite materials, that the photoalignment of liquid crystal can substantially be improved when using alignment layers made from photoalignment composite materials. These composites contain at least one photoalignment material. The other components of the photoalignment composite material may or may be not photosensitive, as conventional polyimide materials, for instance. We show that by a proper choice of the components, the properties of the photoalignment materials, made by photoalignment composites, can be tailored in a broad range, resulting in higher sensitivity, and thus shorter exposure time, uniform and smooth photoalignment topography (without domains and sandy structures) resulting in high image contrast. High-quality photo-patterning of the liquid crystal alignment is demonstrated in this work with a photoalignment composite material containing one of our photoalignment materials and a conventional polyamide alignment material.